CC connects but then sits there doing nothing. What do I do?

Calibre Companion connects to calibre as a "device", which means that calibre is in charge. After Calibre Companion connects, you use calibre to send books to your device and delete books from your device, just as if your device were connected using a cable.

After connecting, go to your computer running calibre, select some books, then click on the "Send to device" button.